import os
import shutil
import aiohttp

from exceptions import DOWNLOAD_FAIL

async def downloadFileToMemory(url, session : aiohttp.ClientSession):
    print("Downloading", url)
    try:
        async with session.get(url) as resp:
            result = await resp.read()
            if len(result) == 0:
                raise DOWNLOAD_FAIL("received 0 bytes")
            else: 
                return result
    except Exception as e:
        print(url, e)
        raise DOWNLOAD_FAIL(e)
    
async def save_to_file(url, out_file, session):
    file_bytes = await downloadFileToMemory(url, session)

    if os.path.exists(out_file):
        shutil.copy(out_file, out_file + "_bck")

    with open(out_file, "wb") as binary_file:
        binary_file.write(file_bytes)

    return file_bytes